Railway traffic controlling apparatus



C. S. SNAVELY RAILWAY TRAFFIC CONTROLLING APPARATUS 5 Sheets-Sheet l May 19, '1931.

Original Filed Oct. 18, 1925 INVENTO c. s. SNAVELY RAILWAY TRAFFIC CONTROLLING APPARATUS v 6v$heetsr$het May 19, 1931.

Original Filed Oct.

. 3 Sheets-Shet 3 AWE c. s. SNAVELY ori inal Filed Oct. 18, 1926 RAILWAY TRAFFIC CONTROLLING APPARATUS May 19, 1931.

Reissued May 19, 1931 UNITED STATES PATENT OFFICE MB 8. SNAVELY, 05E HTTSIBURGE, PENNSYLVANIA, ASSIGNOB TO" THE UNION SWITCH & SIGNAL CGKPAN-Y, OF SWISSVALE, PENNSYVLANM, A' C'GEPOZBATIQN O1? IEIINSYLVANIA RAILWAY TRAFFIC GONTROELING APPARATUS will] No. 1,743,980, dated April 23, 1928, Serial No. 142,162, filed October 18, 1926. Application for reissue filed November 1930. Serial No. 498,192.

My invention relates to railway traflic controlling a paratus, and particularly to ap- Paratus o? the ty wherein coded current impulses are applied to the track ra1ls for the purpose of controlling train-carried governin mechanism or wayside signals or both.

I w lll describe several forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. I is a diagrammatic view showing one form of apparatus embodying my invention, the appmratus in the form here shown being arranged for the control of train-carried governing mechanism. Fig. 2 is a diagrammatic view similar to Fig. I but modified for the control of wayside signals as wellas traincarried' governing mechanism, and also embodying my invention. Fig. 3 is a view show- 1 a modification of the apparatus shown in Fig. I and embodying my invention. Fig. 4

is a view showing still another modification of the apparatus shown in Fig. l and also eabodying my invention. Fig. 5 s a new s wing a modified form of apparatus embodying my invention arranged for use on an alternating current electric railway and adapted for the control of wayside signals as Well as train-carried governing mechamm. Fig. 6 is a view showing a modificati'on' of the ap aratus shown in Fig. 5 and likewise embo ying my invention.

Similar reference characters refer to simila r arts in each of the several'views.

eferrin first to Fig, 1, the reference characters and I designate the track rails of a. stretch of railway track over which traflic normally moves in the direction indim cated hy the arrow. These rails are divided by insulated joints 2 to form aplurality of successive track sections of which only three completesect-ions A-B; B--C and C-l) are shown in the drawings. Each tracksection is providedwith a track transformer '1 having a secondary 5 which isconstantly connected acrosathe track rails adjacent the exit end of th! section through the usual limiting impedanee 6 The. primary 7 of each track transformer is at times connected with a source of alternating current which is not shown in the drawings'but is indicated by the reference character A. C. The supply of alternating current from this source to the primary 7 is controlled by a contact 18 ofa coding device explained hereinafter. Each track section is furthcrprovid'ed with a track relay R which is connected across the rails adjacent the entrance end of the section.

Each track section is provided with a coding relay S which comprises two windings X and Y each made up of three coils 14', 15 and 16'. The armature of this relay controls two contacts 17 and 18 which are arranged to occupyv one extreme position or the other accordin as the armature is attracted by winding or winding Y. Each coding relay is supplied with unidirectional current from a transformer J through a rectifier Q, the primary of each transformer J being connected with a source of alternating current which is not shown in the drawings but which is indicated by the reference character A. C. The supply of current from each rectifier Q- to the coding relay S is controlled by two selector relays E and E, which in turn are controlled in the manner hereinafter explained. Referring for example to the coding relay S located at the point B, when relay E is energized, current flows from the rectifier Q through front contact of relay E, coils 14 of windings Y and X in series, and front contact 63 of relay E to the rectifier Q. Coil 14 of relay is provided with a shunting ath which passes from the lowerterminal 0 this coil through front contact 63 of relay-E left-hand'point of contact 17 of relay S to the upper terminal of the coil 14. Coil 14 of winding Y is rovided with a similar shunting path whic passes from the lower terminal of this coil through front contact 60 of relay E and the righthand' point of contact 17 to the upper termi' nal of coil 14. When relay E is energized; relay S operates to close contact 18' periodically, so that the alternating current supplied to the track rails of section A-B bythe track transformer T is periodically interrupted;

Referring now to the coding relay S at location C when relay E is deenergized' and relay E is energized the operating circuit apparent from the drawings without detailed explanation. Due to the increased reactance of the windings X and Y when coils 14 and 15 are both included in the operating circuit,

the operation of the relay S is slower than when only one coil of each winding is energized.

Referring now to the coding relay S shown at location D, when both of the selector relays E and E are deenergized, the operating circuit for the coding relay is from recti fier Q, through back contact 60 of relay E back contact 35 of relay E coils 16, 15 and 14 of winding Y,-coils 14, 15 and 16 of-winding X, back contact 31 of relay E and back contact 63 of relay E to the rectifier Q. The shunting paths for the windings X and Y will be ap arent from the foregoing explanation. wing to the still greater reactance of the windings X and Y when all three coils of each winding are included in the operating circuit, the operation of the relay S is still slower than when two coils of each winding are included in the circuit. It follows from the foregoing that the periodic interruptions of, the alternating current supplied to the rails of section C-D are at a relatively low frequency, while the periodic interruptions of the current supplied to therails of section B-C are at an inter mediate frequency, and the periodic interruptions of the current supplied to section AB are-at a relatively high frequency.

These frequencies I will termthe low speed code, the medium speed code, and the high speed code, respectively.

The track relay R for each section is, of course, periodically energized when the section is not occupied by a train, the frequency of energization of this relay being'the same as the frequency of interruption of the alternating current supplied to the rails of the section, that is, the same as the frequency of operation of contact 18 of the coding relay S for such section. Y

Each section is provided with the two transformers G and G each having two primaries 45 and 46 and a secondary 47. When a track relay R isperiodically operated, periodically varying fluxes of a frequency corresponding to the frequency of operation of relay R are created in the cores of the two associated transformers G and G \Vhen relay R is closed, unidirectional current is supplied'from asuitable source, such as'a rectifier 9 to the primaries 45 of transformers G} and G in parallel. When relay R is open, however, unidirectional current is supplied to primaries 46 of the two transformers G and G from the rectifier 9. Each rectifier 9 is connected with the secondary of a transformer K, the primary of which is constantly supplied with alternating current from a source not shown in the drawin s but indicated by the reference character C. It will be noted that direct current flows in opposite directions through the two primaries 45 and 46 of each transformer G and G and it follows that when relay R is in operation the magnetic fluxes in the two transformers are periodically reversed at a frequency corresponding to the frequency of interruption of the current in the track rails. Secondary 47 of transformer G is connected through a rectifier L, with the selector relay E whereas secondary 47 of transformer Gr is connected through a rectifier L with the selector relay E The variations in the flux in the core of transformer G creates surges of current in relay E and the same thing is true of transformer G and relay E It is well known that if a transformer is designed so that for an input of one amplitude and frequency the core is substantially saturated, acertain amount of energy will be delivered at that frequency and at least as much energy will be delivered at higher frequencies, but that at lower frequencies with the same amplitude of electromotive force a smaller amount of energy is delivered by the transformer. I take advantage of this principle to select between the three codes de-v livered to the track rails of each section by the coding relay S. To do this, the parts are so proportioned that when the flux in transformer G is being reversed at the relatively low frequency, the core of this transformer is substantially saturated and relay E is supplied with suflicient energy to cause it to close its front contacts. It follows that this relay will also be energized when the flux is being reversed at the higher frequencies. The parts are further so proportioned that when the flux in transformer G is being reversed at either of the intermediate or the hi h frequency, the core of this transformer 1s. substantially saturated and sufficient energy is supplied to relay E v to cause it to close its front-contacts. At the low frequency of in terruption, however, relay E is deenergized because the reversals of flux are of the same amplitude asbefore but the energy delivered by this transformer to relay E is insuflicient to energize the relay.

As shown in the drawings, the section immediately to the right of point D is occupied by a train V, so that track relay R for such sec tion is continuously deenergized. Relays E and E at point D are therefore deenergized because the current flowing in the primary windings of! transformers G and G is unidirectional. Coding relay S at locationv D is therefore operating at'rts lowest rate, sothat thecnrrem in section C--D is interrupted at the 150w speed: rate. All location C, relu. E

is eneoros'uedond relay E is decnergi so that. hag-relay S. is operating at its intermedibte rate, with the result thatthe current in section M is being interrupted at the intermediate speed rate. At location B, rehys E and E are: both: energized, so that coding relay S-isoperatimg at its highest rate, with the result thM the current in the of section Ar-B is being interrupted in accordance with the high speed code.

The apparatus shown in- Fig. I is suitable for cooperation with any form oi traiwcar ried mechanism which is controlled by cur-- rent in the truck rails, and is selectively responsive to the frequency of interruption of such current. For example, the trarmcap riod mechanisnmay be similar-to that shown and described in my as -pending application filed May 29, 1926, Serial No. 1:12am, for

m railway trafie controlling apparatus, it being.

. asi-n Fig. 1".

understood that the mechanism show-1r in that application would be modified by the addition of a thirdtmnsformer andathird relay E to take advantage of the three-codes in II the track rails provided by the trackway apparauus shown in Fig. 1? ofthe present appli-- cation. I

Referring now to Fig. 2, the apparatus shown in-tirisview is the same as that shown in Fig. 1, except that a third transformer G and athird relay E have been added, theseparts being so proportioned that the relay E becomes energized only in response to the high speed code. The operation of there lays E and E, and the control of thecoding relay S by these relays, are the same The selectorrcla-ys E, E and E-"areutilized inth-is view to control a wayside signalM having a-high speed lamp 3, a medium speed lamp 3, a low speed lamp 3, anda stop lamp 3. When relay E is energi-zed, the highspeed lam-p 3 islightod, the circuit being flrom terminal P of a suitable source of cunent, througlifront contact 1%). relay E andf'lam-p 3 to terminal 0. of

the same source of-current. When relay E" is open and relay E is closed, the medium speed lamp 3" is opened through back. contact "of relay E" and front contact 11, of relay E". when relays E and E are both opened and relay E is: closed, the low speed lamp 23 is ligited, the circuit being through back contact 19 of relay E, backcontact 11 ofrelav E and-front contact- 1201' relay E.

"When lill three relaysE are open, the stoplamp 3* is lighted, the circuit including back contacts 10, 11 and 12 of the three relays; It willbeseenthat the only purpose ofrel'aryll ist'o 'i've afourt-h indication in the waysidesigna corresponding tothe fourth indication given on a train when the high speed code is supplied to the track rails.

Referring now to Fig. 3, the apparatus shown in this View is similar to that shown in Fig. 1, except that each track section is provided with only one transformer-G and one selector relay E, while the coding rel ay S has only two coil s 14 and- 15 in each of its windings X, and Y. WVhen a track section occupied, relay R isdeenergized so that rcl'ay E is openwith the result that a low speed code is applied to the rails of the section next in the rear. When a section is unoccupied, however, relay E is energized rewhether-the low speed or the high speed code is: applied to the rails of the section, so that the high speed code will be applied to the rails ofthe section next to therear; In other'words, trans-formerK and relay E are'so proportioned that the relay is energized in response to either code,-but'th-is-relay is, of course, not energized in responseto: false alternating current constantly supplied to the track rails when the section is occupied. 1 I

The apparatus shown in- Fig. 3 is suitable for use with the train-carried mechanism shown: in my co-pending application, Serial No. 112,491, referred to! hereinbefore.

Referring now to Fig. 4, the apparatus shown in this View is similar to that shown. in Fig. 1, except that a wayside signal N is added, whichsignal is controlled by the selector relays E and E A furtherdifference between the two views is that in Fig. 4: the periodically interrupted currents are gen-- stated at' a central" point and transmitted to each track section through line wires 19-, 20

and 21. Eoeated'at such central point is a motor 4 constantly operated from asource of alternating current A. G1, which motor drives two commutators H and Mi The coded currents are supplied by a transformer 13, the primary of which is constantly connected with: the source of alternatingcurrent A. C. One terminal oi? the secondary transformer 13 is connected with a common line wire 21, while the other terminal is connected with a medium speed code wire 20 through the commutator M and with a high speed code wire 1'9 through the commutator H. When relay E is energized, the primary 7 of track transformer T is connected across the line wires 19 and 21' throuph front contact of.

relay E. so that the high speed code is ap- J plied to the rails of the section in the rear. \Vhcn relay E is open, however, the primary 7' of transformer T is connected with the medium speed-- code wires 20 and 21, so that the medium's'peed code is applied to the rails both relays E and E are open, thestop lamp 3 is lighted. The circuits for these lamps will be apparent from the drawingsand need not be traced in detail. I

In Fig. 4 the rimary current for transformers G and is supplied by a battery P instead of by a transformer K and rectifier 9 as in the preceding views.

The apparatus shown in Fig. 4 is suitable for use with the train-carried governing mechanism shown in my copending application, Serial No. 112,491, referred to hereinbefore.

Referring now to Fig. 5, I have here shown a system embodying my invention applied to a railway the propelling energy for which is alternating current. Inductive bonds 25 are provided in accordancewith the usual practice to conduct the propulsion current around the insulated joints-2. The coded. currents are supplied from a central location as in Fig. 4 over line wires 19, 20 and 21 and a steady alternating current is also supplied fromthe transformer 13 to line wires 21and 22. The unidirectional current for the transformers G2 and G is furnished from the line wires 21 and 22 through a transformer 23, a rectifier 24 and a smoothing reactance 26. The supply of coded current is controlledv as in Fig. 4 by contact 35 of relay E", and a wayside signal N is controlled jointly by the relays E and E A filter.

devlce W is interposed between the track rails 1 and 1 and the track relay which is here designated R which filter device freely transmits the alternating trackcircuit current, that is, the current which is periodically interrupted to produce the codes. This filter device, however, will not transmit alternating current of the propulsion frequency. The track relay R is a direct current relay furnished with unidirectional current from a rectifier 22 which in turn receives current from the filter device W.

The apparatus shown in Fig. 5 is suitable for use in connection with the train-carriedv governing mechanism shown in my coending application, Serial No. 112,491, re erred to hereinbefore. H

Referring now to F ig. 6, the apparatus here shown is the same as that shown in Fig.

5, except that the neutral track relay R inv Fig. 5is replaced by a polarized track relay R in Fig. 6. This relay R receives energy from the filter device W through a rectifier 22, a smoothing reactance 27 and a transformer 28. An impulse of one polarity isobtained from the secondary of transformer 28 when a code impulse is applied to the track, andan impulse of the opposite polarity is received from the secondary of transformer 28 when a code impulse in the track ceases. These opposite impulses applied to the relay R at the beginning and end of each track code impulse cause the relay to operate its expensive alternating current relays. In Figs. 5 and 6 I have shown how complete in-.

stallations may be made using direct current relays only, thereby providing maximum protection at minimum cost of both installation and maintenance.

In Figs. 1, 2 and 3, I have shown how any number of proceed indications within the limits of the code system may be transmitted from signal location to signal location withoutthe use of line wires, thereby producing a wirelesssignal system for more than two proceed indications. The only line Wires required in the systems shown in these views would be those for the transmission of power which would be necessarv in anv svstem using alternating current.

Furthermore, since the polarized track circuit system, such as is ordinarily used in present day installation, is eliminated, it is not necessary to use special slow-releasing relays to prevent a momentary red or stop indication in the waysidesignal when changing from one proceed indication to another proceed indication. With the systems shown in the present disclosure the stop indication. will never be displayed except in the absence of coded current, in which case, of course, the stop indication is desired. In the systems of the present disclosure the indications always scribed only a few forms of apparatus em bodying my invention, it is understood that various changes and modifications may be madetherein within the scope of the appended'claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a. stretch of railway track divided into sections, a track relay for each section, transformers for eachsection halving diflferent sammtim characteristics, moans control-led by the track relay for each section for creatin in associated transformers periodical y varying fluxes the l retaendee of which vary in accordance with fiequency 'of operation of the track relay, selector relays for each section one connected iith the secondary of each associated transformer 'and each arranged to be energized when and only when the associated transformer is being supplied with flux at afrequency at least ts high as the frequency at which the core of such transformer becomes stunted, and means controlled by the selector relays of each section for supplying current pm'iod-ical ly interrupted at diflerent frequenoies to the rails of the section next in the rear.

2. In combination, a stretch of railway track divided into sections, a track relay for adh section, transformers for each section having different saturation characteristics, means controlled by the track relay for each section for creating in the associated transfior'mors periodically varying fluxes the frequenciaes of which vary in accordance with the requencyoi operation of the track relay, selector "relays for each section one connected with the secondary of each a$ociated transformer and each arranged to be energized when only when the associated transtamer is being supplied with flux at "a freq'uency at least as high as the frequency at which the 'core of such transformer becomes I saturated, signals for the sections controlled 1 session for creating in the core of the assodiated a periodically varying flux, the frequency-of which varies in accordance with thefrequency of operation of the Michaela-y, ase'le'ctor relay for each section I eotmected with the secondary of the assooiated transformer arranged to be enermd when-and only When the transformer is supplied with periodically varyingflux due periodic operation of the associated track relay, and means controlled by the se-' laotor'relay of each section for supplying the rails of the section next in the rear with current periodically interrupted at one frequency or ano'ther according as the relay is energized or dcenergized.

't. In combination, a stretch of railway trlickdivided into sections, a trackrelay for each suction, transformers for each section, having cram saturation characteristics, means 'edntrdlcd by the track relay for each section for creating in-the associated transformers periodically varying fluxes the freq' ncies of which vary in'aooo rda-nce with the frequency of operation or the track relay,selector relays for each section one connected with the secondary of each associated trans; former and each arranged to he energized when and only when the associated transformer is being supplied with flux at a frequency at least as hi h as the frequency at which the core of $1151 transformer becomes saturated, transmission lines-extending along the trackway and carrying currents periodically interrupted at different frequencies, and means controlled by the selector relays of each section for connectingjone or another of said transmission lines with the rails of the section next in the rear. 7 Y

5. In combination, a stretch of railway track divided intovsecti'ons, a track relay for each section, transformers for each section having different saturation characteristics, means controlled by the track relay for each section for creating in the associated transformers periodical y varying flux-es the frequencies of which vary in accordance with the frequency of operation of the track relay, selector relays for each section one connected with the secondary of each associated trans former and each arranged to be energized when and only when the associated transformer is being supplied with has at a fre quency at least as high as the frequency "at which the core of such transformer becomes saturated, signals for the sections controlled by said selector relays, transmission lines extending along the trackway and carr'yi-n currents periodically interrupted at di erent frequencies, and means controlled by the selector relays of each section for connecting one or another of said transmission lines with the rails of the section next in the rear.

6. In combination, a stretch of railway track divided into sections and carrying alternating propulsion current of one frequency, a track relay for each section, transformers for each section having different saturation characteristics, means controlled by the'track relay for each section for'creati-ng in'the associated transformers periodically varying fluxes the frequencies of which vary in accordance with the frequency of operation of the track relay, selector relays for each section one connected with the-secondary of each associated transformer and each arranged to be energized when and only when the associated transformer is being supplied with flux with frequency at least as high as the frequency at which the core of such transformer becomes saturated, and means controlled by the selector relays of each section for supplying to the rails of the section next in the rear an a-lternating si'gnalin'g current of a frequency different from that of the propulsion current and periodically interruptedat difierent'frequencies depending upon the energization of said selector relays. I

7. In combination, a stretch of railway track divided into sections and carrying alternating propulsion current of one frequency, a track relay for each section, transformers for each sect-ion having different saturation characteristics, means controlled by the track relay for each section for creatin in the associated transformers periodica ly varying fluxes thefrequencies of which vary in accordance with the frequencyof operation of the track relay, selector relays for each section one connected with the secondary of'each 3850-,

ciated transformer and each arranged to be energized when and only when the associated transformer is being supplied with flux at a frequency at least as high asthe frequency at which the core of such transformer becomes saturated, means controlled by said selector relays of eachsection for supplying to the rails of the section next in the rear alternating signaling current of a frequency different from that of the propulsion current and periodically interrupted at a different frequency, and filtering means interposed between each track relay and the rails of the associated section for freely passing alternating current of the signaling frequency, but not of the pro pulsion frequency.

8. In combination, a stretch of railway track divided into sections, a track relay for each section, a transformer for each section, means controlled by the track relay of each section for creating in the core of the associated transformer a periodically varying flux the frequency of which varies in accordance with the frequency of operation of the track relay, a selector relay for, each section connected with the secondary of the associated transformer and arranged to be energized when and only when the transformer is being supplied with periodically varying flux due to periodic operation of the associated track relay, transmission lines extending along the trac way and carrying currents periodically interrupted at different frequencies, and -means controlled by the selector. relay of each section for connecting one or another of said transmission lines with the rails of the section next in the rear according as the selector relay is energized or not.

9. In combination, a stretch of railway track divided into sections, a track relay having a winding connected with the rails of each section and'responsive to periodic interruptions of alternating current in such rails, a plurality of decoding relays associated with g each section, means for selectively energizing 9 said decoding rela s in accordance with the rate of operation 0 the associated track relay, means controlled by the decoding relays for 7 each section for supplying alternating currentto the rails of the section next in the rear periodically interrupted at different-rates actrack divided into sections, a track relay have ing a winding connected with the rails of each section and responsive to periodic in terruptions of alternating current in such rails, a plurality of decoding relays associated with each section, means for selectively energizing said decoding relays in accordance with the rate of operation of the associated track relay, and means controlled by the decoding relays for each section for supplying alternating current to the rails of the section next in the rear periodically interrupted at different rates according to the conditions of the decoding relays.

11. In combination, a stretch of railway track divided into-sections, a track relay and at least two decoding relays E and E for each section, each track relay being responsive to periodic interruptions of alternating current in the track rails, means controlled by the decoding relays for each section for supplying the rails of the section next in the'rear with alternating current periodically interrupted at one rate when both relays are deenergized, ata second rate when relay E is energized and relay E deenergized, and at a third rate when both relays are energized, means controlled by each track relay for energizing the associated relay E in response to alternating current periodically interrupted at the first rate and for energizing both relays E and E in response to alternating current periodically interrupted at the second rate, and signals for the'sections controlled by said decoding relays.-

12. In combination, a stretch of railway track divided into sections,a track relay having a winding connected with the rails of each section and responsive to periodic interruptions of current in such rails, a plurality of decoding relays associated with each section, means for selectively energizing said decoding relays in accordance with the rate of operation of the associated track'relay, means controlled by the decoding relays for each section for supplying current to the rails of the section next in the rear periodically interrupted at different rates according to the conditions of the decodin relays, and signals for the sections controlle by said de coding relays.

13. In combination, a stretch of railway track divided into sections, a track relay having a winding connected with the Tails of each section and, responsive to periodic interruptions of current in such rails, 21; plurality of decoding relays associated with each section, means for selectively energizing said decoding relays in accordance with the rate of operation of the associated track relay, and means controlled by the decoding rela s for each section for supplying current to the rails of the section next in the rear periodically interrupted at different rates according to the conditions of the decoding relays.

14. In combination, a stretch of railway track divided into sections, a track relay having a winding connected with the rails of each section and responsive to periodically 1 varying current in such rails, a plurality of decodin relays associated with each section, means or selectively energizing said decoding relays in accordance with the rate of operation of the associated track relay, means controlled by the decoding relays for each section for supplying current to the rails of the section next in the rear periodically varied at diflerent rates according to the conditions of the decoding relays, and signals I for the sections controlled by said decoding relays.

In testimony whereof I aflix my signature.

CLARENCE S. SNAVELY. 

